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Search: id:A081650
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| A081650 |
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Least nonsquare congruent to i^2 (mod k^2) for all 0<k<=n, i being any integer. |
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+0
1
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| 2, 5, 13, 73, 409, 801, 1584, 2241, 30601, 30601, 78409, 156825, 862416, 862416, 7929009
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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Mark A. Herkommer, Number Theory, A Programmer's Guide, McGraw-Hill, New York, 1999, page 315.
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EXAMPLE
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a(3) = 13 because for (mod 1) (A000037) is the set of all non squares, for (mod 4) (A079896) is the set beginning {5, 8, 12, 13, 17, 20, 21, 24, 28, 29, ...} and for (mod 9) (A081642) is the set beginning {10, 13, 18, 19, 22, 27, 28, 31, 37, 40, ...}. The first element of the intersection of these three sets is 13.
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PROGRAM
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(PARI) t=2:for(n=1, 50, for(m=t, 10^9, if(!issquare(m), f=0:for(k=1, n, if(!issquare((m%(k^2))), f=1:break)): if(!f, print1(m", "):t=m:break))))
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CROSSREFS
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Cf. A000037, A079896, A081642, A081643, A081644, A081645, A081646, A081647, A081648, A081649.
Adjacent sequences: A081647 A081648 A081649 this_sequence A081651 A081652 A081653
Sequence in context: A028856 A013497 A128029 this_sequence A092262 A032015 A075736
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 26 2003
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EXTENSIONS
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Edited by Ralf Stephan (ralf(AT)ark.in-berlin.de), Mar 27 2003
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